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Volume 57 Supplement 12

Special Issue: Modelling the Earth’s Magnetic Field: the 10th Generation IGRF

The BGS magnetic field candidate models for the 10th generation IGRF


In this paper we describe the derivation of the BGS candidate models for the 10th generation International Geomagnetic Reference Field. Our data set comprised quiet night-time data from the Èrsted and Champ satellites spanning 1999.2–2004.6 and observatory hourly means spanning 1999.0–2004.0. To improve the secular variation estimates for 2005.0–2010.0, predictions based on application of linear prediction filters to long series of observatory annual means were also used. These data were fitted by a spherical harmonic “parent” model with an internal field of maximum degree 36, a quadratic dependence on time up to degree 8, a linear dependence on time up to degree 12, an external field of maximum degree 2 with linear dependence on time, annual and semi-annual variations, and Dst dependence for degree 1 terms. Additionally for the external field, non-zonal degree 1 coefficients in the Geocentric Equatorial Inertial reference frame with annual variations and dependence on the Interplanetary Magnetic Field Y-component are included. The candidate models were then based, for the main field, on an extrapolation to 2005.0 of the truncated parent model, and for the secular variation, on its extrapolation to 2007.5. This latter set of coefficients was then used to generate a synthetic data set at the Earth’s surface and this set was augmented with long term linear predictions of observatory annual means, to produce the final candidate secular variation model at 2007.5.


  • Hapgood, M. A., Space physics coordinate transformation: A user guide, Planetary and Space Science, 40, 711–717, 1992.

    Article  Google Scholar 

  • Holme, R., Modelling of attitude error in vector magnetic data: application to Èrsted data, Earth Planets Space, 52, 1187–1197, 2000.

    Article  Google Scholar 

  • Langel, R. A. and R. H. Estes, Large-scale, near-Earth magnetic fields from external sources and the corresponding induced internal field, J. Geophys. Res., 90, 2487–2494, 1985.

    Article  Google Scholar 

  • Lesur, V., S. Macmillan, and A. Thomson, Magnetic field model with daily variations of the magnetospheric field and its induced counterpart in 2001, Geophys. J. Int., 160, 79–88, 2005.

    Article  Google Scholar 

  • Lowes, F. J. and N. Olsen, A more realistic estimate of the variances and systematic errors in spherical harmonic geomagnetic field models, Geophys. J. Int., 157, 1027–1044, 2004.

    Article  Google Scholar 

  • Macmillan, S. and J. M. Quinn, The 2000 revision of the joint UK/US geomagnetic field models and an IGRF2000 candidate model, Earth Planets Space, 52, 1149–1162, 2000.

    Article  Google Scholar 

  • Maus, S. and P. Weidelt, Separating magnetospheric disturbance magnetic field into external and transient internal contributions using 1D conductivity model of the Earth, GRL, 31(12), L12614, 10.1029/2004GL020232, 2004.

    Article  Google Scholar 

  • McLean, S., S. Macmillan, S. Maus, and V. Lesur, A. Thomson, and D. Dater, The US/UK World Magnetic Model for 2005–2010. NOAA Technical Report NESDIS/NGDC-1 available at and, 2004.

    Google Scholar 

  • Olsen, N., A model of the geomagnetic field and its secular variation for epoch 2000 estimated from Èrsted data, Geophys. J. Int., 149, 454–462, 2002.

    Article  Google Scholar 

  • Sabaka, T. J., N. Olsen, and R. A. Langel, A comprehensive model of the quiet-time, near-Earth magnetic field: phase 3, Geophys. J. Int., 151, 32–68, 2002.

    Article  Google Scholar 

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Correspondence to Vincent Lesur.

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Lesur, V., Macmillan, S. & Thomson, A. The BGS magnetic field candidate models for the 10th generation IGRF. Earth Planet Sp 57, 1157–1163 (2005).

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Key words

  • IGRF
  • geomagnetic field
  • geomagnetic secular variation